a novel distributed frequency allocation scheme named as exponential distribution based frequency allocation (EDFA) is proposed in Fractional Frequency Reuse (FFR) aided OFDMA networks. EDFA has a flexible adjustment between fairness and throughput. Simulation results demonstrate that compared to the proportional fairness (PF) allocation and equal rate allocation (ERA) schemes, EDFA could achie...

This paper incorporates a comprehensive BER simulation study undertaken on the effectiveness of a multi-user MIMO OFDMA wireless communication system on encrypted data transmission. The channel encoded and spatially multiplexed multi-user MIMO OFDMA system under investigation implements Pre-RSNA cryptographic algorithm. The simulated system deploys three linear signal detection schemes (Equaliz...

In 4G technology especially LTE relaying and orthogonal frequency division multiple access (OFDMA) are widely accepted techniques in downlink. To obtain ubiquitous coverage with high data rate to user terminals even in difficult channel conditions (e.g. cell edge) a centralized RRM algorithm has been proposed for cellular fixed relay networks in downlink OFDMA. The proposed method provides the ...

Orthogonal Frequency Division Multiple Access (OFDMA) is one of the most promising, demanded and researched modulation and access methods for future mobile wireless networks. Emerging technologies, like Worldwide Interoperability for Microwave Access (WiMAX) or Long Term Evolution (LTE), are adopting OFDMA due to its high spectral efficiency, scalability for high amounts of users and mobility s...

Sparse code multiple access (SCMA) is one of the promising candidates for new radio interface. The generation communication system expected to support massive user with high capacity. However, there are numerous problems and barriers achieve optimal performance, e.g., multiuser interference power consumption. In this paper, we present optimization methods enhance spectral energy efficiency SCMA...

Benefits of network coding towards enhancing communication quality, both in terms of robustness or data transmission rates, make it a significant candidate as a future networking technology. Conventionally, network coding is mostly used in wired infrastructures, where transmission errors between nodes are negligible. Capturing the provided benefits of network coding via straightforward extensio...

In this paper, the performance of orthogonal frequency division multiple access (OFDMA) uplink systems over time-varying frequency-selective Rayleigh fading channels is investigated. Expressions of the bit error rate (BER) performance for quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM) signals under channel estimation errors are derived. Based on BER performance, ...

In this letter, we study cell cooperation in the downlink OFDMA cellular networks. The proposed cooperation scheme is based on fractional frequency reuse (FFR), where a cooperation group consists of three sector antennas from three adjacent cells and the subchannels of each cooperation group are allocated coordinately to users. Simulation results demonstrate the effectiveness of the proposed sc...

This article puts forward an examination of using OFDMA method like WiMax for future cellular systems. The main goal of investigation and simulation is Doppler Effect influence on orthogonality disturbance in critical but real situations. The simulation results, allow coming to conclusion that Doppler Effect influence on pilot signals leads to BER increasing. The paper proposes Doppler Effect l...

This paper studied the power allocation and downlink interference issues in orthogonal frequency-division-multiple-access (OFDMA) system to mitigate the interference issues. In Orthogonal Frequency Division Multiplexing Access (OFDMA) frameworks, resource allotment to the subcarrier is crucial attributable to the deficient assets accessible at the base station. In OFDMA, subcarrier and power di...